The present invention relates to a vacuum panel manufacturing process, and in particular a process utilizing a powdered insulation material which is first evacuated of gases and subsequentially loaded and hermetically sealed into an impermeable barrier bag.
Vacuum insulation panels are useful in a variety of environments, and in particular in conjunction with refrigeration apparatus in which they are utilized as insulating panels in the walls of refrigerators and freezers.
Typically a vacuum insulation panel has some type of insulating material, generally microporous powders or microporous sheets of insulating material which are placed into a non-porous bag comprising flexible gas impermeable walls and, after evacuation of all gases, the bag is sealed. Such panels and a method for fabricating them are disclosed in U.S. Pat. No. 5,018,328, assigned to Whirlpool Corporation, the assignee of the present application, the disclosure of said patent being incorporated herein by reference, as well as in U.S. Pat. Nos. 5,076,984 and 4,683,702.
U.S. Pat. No. 4,554,041 discloses a vacuum insulated pipe in which the evacuated insulating space is filled with powder from an evacuated hopper. German Patent 40 40 144 discloses a method for filling a bag with dust-like material wherein the bag and the dust-like material are vacuum evacuated prior to and during filling of the bag.